"Both tactically on the battlefield and at home, he was one of the best SEALs I've ever worked with," said an ex-SEAL Team Six member who served with Shadle for years. "His reputation was that of a great operator, a true friend and a nice guy."

Shadle, a 31-year-old Pennsylvania native, was one of two SEAL Team Six members involved in a serious accident during routine freefall training in Arizona Thursday. Both SEALs were taken to a nearby hospital where Shadle succumbed to his injuries, according to Defense officials. The other SEAL is in stable condition, the Navy said.

"[Shadle] should be remembered as a hero, a father, a friend and an American," Shadle's former SEAL colleague said. "He sacrificed everything for his country."

SEAL Team Six, the unit to which Shadle belonged, is the most elite of the SEAL teams and the one tasked with the historic May 2011 raid that killed al Qaeda leader Osama bin Laden.